The new cartridges work great. It was definitely a neck tension issue. Thank you for all of the assistance, it definitely pointed me in the right direction and gave me a deeper understanding of the inner workings of the sizing/expander die. I was going through the motions without proper understanding. Now comes the fun of bullet pulling and reloading all of the screw-up rounds - a small price to pay for a valuable lesson. Also...taking the NRAs metallic cartridge reloading course next month to get some further knowledge.

HiBC - Good to know there's a veteran in the area that willing to share some expertise. I'm sure I'll need a hand in the future and will PM you when the time comes.